1. Field of the Invention
The present invention relates to an enclosed type electromagnetic switch having a status indication function, and more particularly, to and enclosed-type electromagnetic switch having a status indication function that can show the electromagnetic switch's status on an enclosure.
2. Description of the Conventional Art
In general, a electromagnetic switch is composed of a combination of an electromagnetic conductor and a thermal overload relay. Here, the electromagnetic contactor or direct current relay is a type of electrical circuit switching unit that transfers mechanical motion and current signals by using the principle of an electromagnet, which is installed in a variety of industrial facilities, machines, vehicles, etc. Especially, a relay for electric vehicle is placed in the battery system of electric vehicles such as hybrid vehicles, fuel cell vehicles, golf carts, and forklifts, and serve to switch the main current on or off. Also, the thermal overload relay is a subsidiary device that break a circuit using the thermal expansion characteristics of bimetallic strips embedded in a heater.
Meanwhile, the electromagnetic switch—which switches direct current—is installed between a direct-current generator and an inverter that converts direct-current power to alternating-current power of a commercial frequency and voltage, in environmentally-friendly power generation systems such as solar power generation systems and wind power generation systems, and performs the function of supplying or interrupting the direct-current power to the inverter.
Electromagnetic switches, used for panels for outdoor use, including solar power generation, wind power generation, streetlight control, and night power generation systems, mostly have an enclosed structure because the malfunction and lifetime of devices are strongly affected by exposure to moisture, dust, and impurities. Here, a electromagnetic switch with an enclosure (or case) is referred to as an enclosed type electromagnetic switch.
FIGS. 1 and 2 illustrate the exterior appearance and interior of an enclosed type electromagnetic switch according to the conventional art. The enclosed type electromagnetic switch according to the conventional art has an electromagnetic contactor 3 and a thermal overload relay 4 embedded inside the enclosure 1. The enclosure 1 may be equipped with an on/off button 2 for operating the electromagnetic contactor 3. Also, the electromagnetic contactor 3 may be equipped with auxiliary contacts 5.
FIGS. 3 and 4 illustrate the action of auxiliary contacts of the enclosed type electromagnetic switch according to the conventional art. FIG. 3 shows the electromagnetic switch in the off state, and FIG. 4 shows the electromagnetic switch in the on state.
When a holder 5 is moved downward by the electromagnetic switch 3's interruption operation, a mover 7 moves downward in conjunction with this. Thus, among the auxiliary contacts, NC contacts (contacts b) 8 turn off, and NO contacts (contacts a) 9 turn on. That is, NC movable contacts 8b are separated from NC fixed contacts 8a, and NO movable contacts 9a make contact with NO fixed contacts 9b. 
However, with the enclosed type electromagnetic switch according to the conventional art, the user is not able to know whether the electromagnetic contactor 3 is normally operating or it is tripped (or stopped) in response to an fault signal detected from a load side, because the electromagnetic contactor 3 is embedded inside the enclosure 1, which gives the user the inconvenience of having to open the enclosure 1 of the product to check.